/**
 * Project Name demo
 * File Name Base64
 * Package Name com.huxiaosu.demo.hadoop.utils
 * Create Time 2019/8/16
 * Create by name：liujie -- email: liujie@huxiaosu.com
 * Copyright © 2015, 2018, www.huxiaosu.com. All rights reserved.
 */
package com.huxiaosu.demo.hadoop.utils;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilterInputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

/**
 * Encodes and decodes to and from Base64 notation.
 *
 * <p>
 * Homepage: <a href="http://iharder.net/base64">http://iharder.net/base64</a>.
 * </p>
 *
 * <p>
 * Change Log:
 * </p>
 * <ul>
 * <li>v2.2.1 - Fixed bug using URL_SAFE and ORDERED encodings. Fixed bug
 * when using very small files (~< 40 bytes).</li>
 * <li>v2.2 - Added some helper methods for encoding/decoding directly from
 * one file to the next. Also added a main() method to support command
 * line encoding/decoding from one file to the next. Also added these
 * Base64 dialects:
 * <ol>
 * <li>The default is RFC3548 format.</li>
 * <li>Using Base64.URLSAFE generates URL and file name friendly format as
 * described in Section 4 of RFC3548.
 * http://www.faqs.org/rfcs/rfc3548.html</li>
 * <li>Using Base64.ORDERED generates URL and file name friendly format
 * that preserves lexical ordering as described in
 * http://www.faqs.org/qa/rfcc-1940.html</li>
 * </ol>
 * <p>
 * Special thanks to Jim Kellerman at <a href="http://www.powerset.com/">
 * http://www.powerset.com/</a> for contributing the new Base64 dialects.
 * </li>
 *
 * <li>v2.1 - Cleaned up javadoc comments and unused variables and methods.
 * Added some convenience methods for reading and writing to and from files.
 * </li>
 * <li>v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on
 * systems with other encodings (like EBCDIC).</li>
 * <li>v2.0.1 - Fixed an error when decoding a single byte, that is, when the
 * encoded data was a single byte.</li>
 * <li>v2.0 - I got rid of methods that used booleans to set options. Now
 * everything is more consolidated and cleaner. The code now detects when
 * data that's being decoded is gzip-compressed and will decompress it
 * automatically. Generally things are cleaner. You'll probably have to
 * change some method calls that you were making to support the new options
 * format (<tt>int</tt>s that you "OR" together).</li>
 * <li>v1.5.1 - Fixed bug when decompressing and decoding to a byte[] using
 * <tt>decode( String s, boolean gzipCompressed )</tt>. Added the ability to
 * "suspend" encoding in the Output Stream so you can turn on and off the
 * encoding if you need to embed base64 data in an otherwise "normal" stream
 * (like an XML file).</li>
 * <li>v1.5 - Output stream pases on flush() command but doesn't do anything
 * itself. This helps when using GZIP streams. Added the ability to
 * GZip-compress objects before encoding them.</li>
 * <li>v1.4 - Added helper methods to read/write files.</li>
 * <li>v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.</li>
 * <li>v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input
 * stream where last buffer being read, if not completely full, was not
 * returned.</li>
 * <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the
 * wrong time.</li>
 * <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li>
 * </ul>
 *
 * <p>
 * I am placing this code in the Public Domain. Do with it as you will. This
 * software comes with no guarantees or warranties but with plenty of
 * well-wishing instead!
 * <p>
 * Please visit <a href="http://iharder.net/base64">http://iharder.net/base64</a>
 * periodically to check for updates or to contribute improvements.
 * <p>
 * author: Robert Harder, rob@iharder.net
 * <br>
 * version: 2.2.1
 */


public class Base64 {

    /* ******** P U B L I C   F I E L D S ******** */

    /**
     * No options specified. Value is zero.
     */
    public final static int NO_OPTIONS = 0;

    /**
     * Specify encoding.
     */
    public final static int ENCODE = 1;

    /**
     * Specify decoding.
     */
    public final static int DECODE = 0;

    /**
     * Specify that data should be gzip-compressed.
     */
    public final static int GZIP = 2;

    /**
     * Don't break lines when encoding (violates strict Base64 specification)
     */
    public final static int DONT_BREAK_LINES = 8;

    /**
     * Encode using Base64-like encoding that is URL and Filename safe as
     * described in Section 4 of RFC3548:
     * <a href="http://www.faqs.org/rfcs/rfc3548.html">
     * http://www.faqs.org/rfcs/rfc3548.html</a>.
     * It is important to note that data encoded this way is <em>not</em>
     * officially valid Base64, or at the very least should not be called Base64
     * without also specifying that is was encoded using the URL and
     * Filename safe dialect.
     */
    public final static int URL_SAFE = 16;

    /**
     * Encode using the special "ordered" dialect of Base64 described here:
     * <a href="http://www.faqs.org/qa/rfcc-1940.html">
     * http://www.faqs.org/qa/rfcc-1940.html</a>.
     */
    public final static int ORDERED = 32;

    /* ******** P R I V A T E   F I E L D S ******** */

    private static final Log LOG = LogFactory.getLog(Base64.class);

    /**
     * Maximum line length (76) of Base64 output.
     */
    private final static int MAX_LINE_LENGTH = 76;

    /**
     * The equals sign (=) as a byte.
     */
    private final static byte EQUALS_SIGN = (byte) '=';

    /**
     * The new line character (\n) as a byte.
     */
    private final static byte NEW_LINE = (byte) '\n';

    /**
     * Preferred encoding.
     */
    private final static String PREFERRED_ENCODING = "UTF-8";

    private final static byte WHITE_SPACE_ENC = -5; // Indicates white space
    private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign

    /* ******** S T A N D A R D   B A S E 6 4   A L P H A B E T ******** */

    /**
     * The 64 valid Base64 values.
     */

    /*
     * Host platform may be something funny like EBCDIC, so we hardcode these
     * values.
     */
    private final static byte[] _STANDARD_ALPHABET = {(byte) 'A', (byte) 'B',
            (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G', (byte) 'H',
            (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N',
            (byte) 'O', (byte) 'P', (byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T',
            (byte) 'U', (byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z',
            (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f',
            (byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k', (byte) 'l',
            (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r',
            (byte) 's', (byte) 't', (byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x',
            (byte) 'y', (byte) 'z', (byte) '0', (byte) '1', (byte) '2', (byte) '3',
            (byte) '4', (byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9',
            (byte) '+', (byte) '/'
    };

    /**
     * Translates a Base64 value to either its 6-bit reconstruction value or a
     * negative number indicating some other meaning.
     */
    private final static byte[] _STANDARD_DECODABET = {
            -9, -9, -9, -9, -9, -9, -9, -9, -9,             // Decimal 0 - 8
            -5, -5,                                         // Whitespace: Tab, Newline
            -9, -9,                                         // Decimal 11 - 12
            -5,                                             // Whitespace: Return
            -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 - 26
            -9, -9, -9, -9, -9,                             // Decimal 27 - 31
            -5,                                             // Whitespace: Space
            -9, -9, -9, -9, -9, -9, -9, -9, -9, -9,         // Decimal 33 - 42
            62,                                             // Plus sign at decimal 43
            -9, -9, -9,                                     // Decimal 44 - 46
            63,                                             // Slash at decimal 47
            52, 53, 54, 55, 56, 57, 58, 59, 60, 61,         // Numbers zero - nine
            -9, -9, -9,                                     // Decimal 58 - 60
            -1,                                             // Equals sign at decimal 61
            -9, -9, -9,                                     // Decimal 62 - 64
            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,   // Letters 'A' - 'N'
            14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O' - 'Z'
            -9, -9, -9, -9, -9, -9,                         // Decimal 91 - 96
            26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a' - 'm'
            39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n' -'z'
            -9, -9, -9, -9                                  // Decimal 123 - 126
    };

    /* ******** U R L   S A F E   B A S E 6 4   A L P H A B E T ******** */

    /**
     * Used in the URL and Filename safe dialect described in Section 4 of RFC3548
     * <a href="http://www.faqs.org/rfcs/rfc3548.html">
     * http://www.faqs.org/rfcs/rfc3548.html</a>.
     * Notice that the last two bytes become "hyphen" and "underscore" instead of
     * "plus" and "slash."
     */
    private final static byte[] _URL_SAFE_ALPHABET = {(byte) 'A', (byte) 'B',
            (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G', (byte) 'H',
            (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N',
            (byte) 'O', (byte) 'P', (byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T',
            (byte) 'U', (byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z',
            (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f',
            (byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k', (byte) 'l',
            (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r',
            (byte) 's', (byte) 't', (byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x',
            (byte) 'y', (byte) 'z', (byte) '0', (byte) '1', (byte) '2', (byte) '3',
            (byte) '4', (byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9',
            (byte) '-', (byte) '_'
    };

    /**
     * Used in decoding URL and Filename safe dialects of Base64.
     */
    private final static byte[] _URL_SAFE_DECODABET = {
            -9, -9, -9, -9, -9, -9, -9, -9, -9,                 // Decimal 0 - 8
            -5, -5,                                             // Whitespace: Tab, Newline
            -9, -9,                                             // Decimal 11 - 12
            -5,                                                 // Whitespace: Return
            -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 - 26
            -9, -9, -9, -9, -9,                                 // Decimal 27 - 31
            -5,                                                 // Whitespace: Space
            -9, -9, -9, -9, -9, -9, -9, -9, -9, -9,             // Decimal 33 - 42
            -9,                                                 // Plus sign at 43
            -9,                                                 // Decimal 44
            62,                                                 // Minus sign at 45
            -9,                                                 // Decimal 46
            -9,                                                 // Slash at 47
            52, 53, 54, 55, 56, 57, 58, 59, 60, 61,             // Numbers 0 - 9
            -9, -9, -9,                                         // Decimal 58 - 60
            -1,                                                 // Equals sign at 61
            -9, -9, -9,                                         // Decimal 62 - 64
            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,       // Letters 'A' - 'N'
            14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,     // Letters 'O' - 'Z'
            -9, -9, -9, -9,                                     // Decimal 91 - 94
            63,                                                 // Underscore at 95
            -9,                                                 // Decimal 96
            26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a' - 'm'
            39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n' - 'z'
            -9, -9, -9, -9                                      // Decimal 123 - 126
    };

    /* ******** O R D E R E D   B A S E 6 4   A L P H A B E T ******** */

    /**
     * In addition to being URL and file name friendly, this encoding preserves
     * the sort order of encoded values. Whatever is input, be it string or
     * just an array of bytes, when you use this encoding, the encoded value sorts
     * exactly the same as the input value. It is described in the RFC change
     * request: <a href="http://www.faqs.org/qa/rfcc-1940.html">
     * http://www.faqs.org/qa/rfcc-1940.html</a>.
     * <p>
     * It replaces "plus" and "slash" with "hyphen" and "underscore" and
     * rearranges the alphabet so that the characters are in their natural sort
     * order.
     */
    private final static byte[] _ORDERED_ALPHABET = {(byte) '-', (byte) '0',
            (byte) '1', (byte) '2', (byte) '3', (byte) '4', (byte) '5', (byte) '6',
            (byte) '7', (byte) '8', (byte) '9', (byte) 'A', (byte) 'B', (byte) 'C',
            (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G', (byte) 'H', (byte) 'I',
            (byte) 'J', (byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N', (byte) 'O',
            (byte) 'P', (byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U',
            (byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z', (byte) '_',
            (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f',
            (byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k', (byte) 'l',
            (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r',
            (byte) 's', (byte) 't', (byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x',
            (byte) 'y', (byte) 'z'
    };

    /**
     * Used in decoding the "ordered" dialect of Base64.
     */
    private final static byte[] _ORDERED_DECODABET = {
            -9, -9, -9, -9, -9, -9, -9, -9, -9,                 // Decimal 0 - 8
            -5, -5,                                             // Whitespace: Tab, Newline
            -9, -9,                                             // Decimal 11 - 12
            -5,                                                 // Whitespace: Return
            -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 - 26
            -9, -9, -9, -9, -9,                                 // Decimal 27 - 31
            -5,                                                 // Whitespace: Space
            -9, -9, -9, -9, -9, -9, -9, -9, -9, -9,             // Decimal 33 - 42
            -9,                                                 // Plus sign at 43
            -9,                                                 // Decimal 44
            0,                                                  // Minus sign at 45
            -9,                                                 // Decimal 46
            -9,                                                 // Slash at decimal 47
            1, 2, 3, 4, 5, 6, 7, 8, 9, 10,                      // Numbers 0 - 9
            -9, -9, -9,                                         // Decimal 58 - 60
            -1,                                                 // Equals sign at 61
            -9, -9, -9,                                         // Decimal 62 - 64
            11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, // Letters 'A' - 'M'
            24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, // Letters 'N' - 'Z'
            -9, -9, -9, -9,                                     // Decimal 91 - 94
            37,                                                 // Underscore at 95
            -9,                                                 // Decimal 96
            38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, // Letters 'a' - 'm'
            51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, // Letters 'n' - 'z'
            -9, -9, -9, -9                                      // Decimal 123 - 126
    };

    /* ******** D E T E R M I N E   W H I C H   A L H A B E T ******** */

    /**
     * Returns one of the _SOMETHING_ALPHABET byte arrays depending on the options
     * specified. It's possible, though silly, to specify ORDERED and URLSAFE in
     * which case one of them will be picked, though there is no guarantee as to
     * which one will be picked.
     *
     * @param options URL_SAFE or ORDERED
     * @return alphabet array to use
     */
    protected static byte[] getAlphabet(int options) {
        if ((options & URL_SAFE) == URL_SAFE) {
            return _URL_SAFE_ALPHABET;

        } else if ((options & ORDERED) == ORDERED) {
            return _ORDERED_ALPHABET;

        } else {
            return _STANDARD_ALPHABET;
        }
    } // end getAlphabet

    /**
     * Returns one of the _SOMETHING_DECODABET byte arrays depending on the
     * options specified. It's possible, though silly, to specify ORDERED and
     * URL_SAFE in which case one of them will be picked, though there is no
     * guarantee as to which one will be picked.
     *
     * @param options URL_SAFE or ORDERED
     * @return alphabet array to use
     */
    protected static byte[] getDecodabet(int options) {
        if ((options & URL_SAFE) == URL_SAFE) {
            return _URL_SAFE_DECODABET;

        } else if ((options & ORDERED) == ORDERED) {
            return _ORDERED_DECODABET;

        } else {
            return _STANDARD_DECODABET;
        }
    } // end getDecodabet

    /**
     * Defeats instantiation.
     */
    private Base64() {
    }

    /**
     * Main program. Used for testing.
     * <p>
     * Encodes or decodes two files from the command line
     *
     * @param args command arguments
     */
    public static void main(String[] args) {
        if (args.length < 3) {
            usage("Not enough arguments.");

        } else {
            String flag = args[0];
            String infile = args[1];
            String outfile = args[2];
            if (flag.equals("-e")) {                          // encode
                encodeFileToFile(infile, outfile);

            } else if (flag.equals("-d")) {                   // decode
                decodeFileToFile(infile, outfile);

            } else {
                usage("Unknown flag: " + flag);
            }
        }
    } // end main

    /**
     * Prints command line usage.
     *
     * @param msg A message to include with usage info.
     */
    private static void usage(String msg) {
        System.err.println(msg);
        System.err.println("Usage: java Base64 -e|-d inputfile outputfile");
    } // end usage

    /* ******** E N C O D I N G   M E T H O D S ******** */

    /**
     * Encodes up to the first three bytes of array <var>threeBytes</var> and
     * returns a four-byte array in Base64 notation. The actual number of
     * significant bytes in your array is given by <var>numSigBytes</var>. The
     * array <var>threeBytes</var> needs only be as big as <var>numSigBytes</var>.
     * Code can reuse a byte array by passing a four-byte array as <var>b4</var>.
     *
     * @param b4          A reusable byte array to reduce array instantiation
     * @param threeBytes  the array to convert
     * @param numSigBytes the number of significant bytes in your array
     * @param options     options for get alphabet
     * @return four byte array in Base64 notation.
     * @since 1.5.1
     */
    protected static byte[] encode3to4(byte[] b4, byte[] threeBytes,
                                       int numSigBytes, int options) {
        encode3to4(threeBytes, 0, numSigBytes, b4, 0, options);
        return b4;
    } // end encode3to4

    /**
     * Encodes up to three bytes of the array <var>source</var> and writes the
     * resulting four Base64 bytes to <var>destination</var>. The source and
     * destination arrays can be manipulated anywhere along their length by
     * specifying <var>srcOffset</var> and <var>destOffset</var>. This method
     * does not check to make sure your arrays are large enough to accomodate
     * <var>srcOffset</var> + 3 for the <var>source</var> array or
     * <var>destOffset</var> + 4 for the <var>destination</var> array. The
     * actual number of significant bytes in your array is given by
     * <var>numSigBytes</var>.
     * <p>
     * This is the lowest level of the encoding methods with all possible
     * parameters.
     *
     * @param source      the array to convert
     * @param srcOffset   the index where conversion begins
     * @param numSigBytes the number of significant bytes in your array
     * @param destination the array to hold the conversion
     * @param destOffset  the index where output will be put
     * @param options     options for get alphabet
     * @return the <var>destination</var> array
     * @since 1.3
     */
    protected static byte[] encode3to4(byte[] source, int srcOffset,
                                       int numSigBytes, byte[] destination, int destOffset, int options) {
        byte[] ALPHABET = getAlphabet(options);

        //           1         2         3
        // 01234567890123456789012345678901 Bit position
        // --------000000001111111122222222 Array position from threeBytes
        // --------|    ||    ||    ||    | Six bit groups to index ALPHABET
        //          >>18  >>12  >> 6  >> 0  Right shift necessary
        //                0x3f  0x3f  0x3f  Additional AND

        // Create buffer with zero-padding if there are only one or two
        // significant bytes passed in the array.
        // We have to shift left 24 in order to flush out the 1's that appear
        // when Java treats a value as negative that is cast from a byte to an int.
        int inBuff =
                (numSigBytes > 0 ? ((source[srcOffset] << 24) >>> 8) : 0)
                        | (numSigBytes > 1 ? ((source[srcOffset + 1] << 24) >>> 16) : 0)
                        | (numSigBytes > 2 ? ((source[srcOffset + 2] << 24) >>> 24) : 0);

        switch (numSigBytes) {
            case 3:
                destination[destOffset] = ALPHABET[(inBuff >>> 18)];
                destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
                destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
                destination[destOffset + 3] = ALPHABET[(inBuff) & 0x3f];
                return destination;

            case 2:
                destination[destOffset] = ALPHABET[(inBuff >>> 18)];
                destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
                destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
                destination[destOffset + 3] = EQUALS_SIGN;
                return destination;

            case 1:
                destination[destOffset] = ALPHABET[(inBuff >>> 18)];
                destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
                destination[destOffset + 2] = EQUALS_SIGN;
                destination[destOffset + 3] = EQUALS_SIGN;
                return destination;

            default:
                return destination;
        } // end switch
    } // end encode3to4

    /**
     * Serializes an object and returns the Base64-encoded version of that
     * serialized object. If the object cannot be serialized or there is another
     * error, the method will return <tt>null</tt>. The object is not
     * GZip-compressed before being encoded.
     *
     * @param serializableObject The object to encode
     * @return The Base64-encoded object
     * @since 1.4
     */
    public static String encodeObject(Serializable serializableObject) {
        return encodeObject(serializableObject, NO_OPTIONS);
    } // end encodeObject

    /**
     * Serializes an object and returns the Base64-encoded version of that
     * serialized object. If the object cannot be serialized or there is another
     * error, the method will return <tt>null</tt>.
     * <p>
     * Valid options:
     * <ul>
     * <li>GZIP: gzip-compresses object before encoding it.</li>
     * <li>DONT_BREAK_LINES: don't break lines at 76 characters. <i>Note:
     * Technically, this makes your encoding non-compliant.</i></li>
     * </ul>
     * <p>
     * Example: <code>encodeObject( myObj, Base64.GZIP )</code> or
     * <p>
     * Example:
     * <code>encodeObject( myObj, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     *
     * @param serializableObject The object to encode
     * @param options            Specified options
     * @return The Base64-encoded object
     * @see Base64#GZIP
     * @see Base64#DONT_BREAK_LINES
     * @since 2.0
     */
    @SuppressWarnings({"ConstantConditions"})
    public static String encodeObject(Serializable serializableObject,
                                      int options) {

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        OutputStream b64os = null;
        ObjectOutputStream oos = null;
        try {
            // ObjectOutputStream -> (GZIP) -> Base64 -> ByteArrayOutputStream
            b64os = new Base64OutputStream(baos, ENCODE | options);

            oos = ((options & GZIP) == GZIP) ?
                    new ObjectOutputStream(new GZIPOutputStream(b64os)) :
                    new ObjectOutputStream(b64os);

            oos.writeObject(serializableObject);
            return new String(baos.toByteArray(), PREFERRED_ENCODING);

        } catch (UnsupportedEncodingException uue) {
            return new String(baos.toByteArray());

        } catch (IOException e) {
            LOG.error("error encoding object", e);
            return null;

        } finally {
            if (oos != null) {
                try {
                    oos.close();
                } catch (Exception e) {
                    LOG.error("error closing ObjectOutputStream", e);
                }
            }
            if (b64os != null) {
                try {
                    b64os.close();
                } catch (Exception e) {
                    LOG.error("error closing Base64OutputStream", e);
                }
            }
            try {
                baos.close();
            } catch (Exception e) {
                LOG.error("error closing ByteArrayOutputStream", e);
            }
        } // end finally
    } // end encode

    /**
     * Encodes a byte array into Base64 notation. Does not GZip-compress data.
     *
     * @param source The data to convert
     * @return encoded byte array
     * @since 1.4
     */
    public static String encodeBytes(byte[] source) {
        return encodeBytes(source, 0, source.length, NO_OPTIONS);
    } // end encodeBytes

    /**
     * Encodes a byte array into Base64 notation.
     * <p>
     * Valid options:
     * <ul>
     * <li>GZIP: gzip-compresses object before encoding it.</li>
     * <li>DONT_BREAK_LINES: don't break lines at 76 characters. <i>Note:
     * Technically, this makes your encoding non-compliant.</i></li>
     * </ul>
     *
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
     * <p>
     * Example:
     * <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     *
     * @param source  The data to convert
     * @param options Specified options
     * @return encoded byte array
     * @see Base64#GZIP
     * @see Base64#DONT_BREAK_LINES
     * @see Base64#URL_SAFE
     * @see Base64#ORDERED
     * @since 2.0
     */
    public static String encodeBytes(byte[] source, int options) {
        return encodeBytes(source, 0, source.length, options);
    } // end encodeBytes

    /**
     * Encodes a byte array into Base64 notation. Does not GZip-compress data.
     *
     * @param source The data to convert
     * @param off    Offset in array where conversion should begin
     * @param len    Length of data to convert
     * @return encoded byte array
     * @since 1.4
     */
    public static String encodeBytes(byte[] source, int off, int len) {
        return encodeBytes(source, off, len, NO_OPTIONS);
    } // end encodeBytes

    /**
     * Encodes a byte array into Base64 notation.
     * <p>
     * Valid options:
     * <ul>
     * <li>GZIP: gzip-compresses object before encoding it.</li>
     * <li>DONT_BREAK_LINES: don't break lines at 76 characters. <i>Note:
     * Technically, this makes your encoding non-compliant.</i></li>
     * </ul>
     *
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
     * <p>
     * Example:
     * <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     *
     * @param source  The data to convert
     * @param off     Offset in array where conversion should begin
     * @param len     Length of data to convert
     * @param options Specified options
     * @return encoded byte array
     * @see Base64#GZIP
     * @see Base64#DONT_BREAK_LINES
     * @see Base64#URL_SAFE
     * @see Base64#ORDERED
     * @since 2.0
     */
    public static String encodeBytes(byte[] source, int off, int len, int options) {
        if ((options & GZIP) == GZIP) {                             // Compress?
            // GZip -> Base64 -> ByteArray
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            GZIPOutputStream gzos = null;

            try {
                gzos =
                        new GZIPOutputStream(new Base64OutputStream(baos, ENCODE | options));

                gzos.write(source, off, len);
                gzos.close();
                gzos = null;
                return new String(baos.toByteArray(), PREFERRED_ENCODING);

            } catch (UnsupportedEncodingException uue) {
                return new String(baos.toByteArray());

            } catch (IOException e) {
                LOG.error("error encoding byte array", e);
                return null;

            } finally {
                if (gzos != null) {
                    try {
                        gzos.close();
                    } catch (Exception e) {
                        LOG.error("error closing GZIPOutputStream", e);
                    }
                }
                try {
                    baos.close();
                } catch (Exception e) {
                    LOG.error("error closing ByteArrayOutputStream", e);
                }
            } // end finally

        } // end Compress

        // Don't compress. Better not to use streams at all then.

        boolean breakLines = ((options & DONT_BREAK_LINES) == 0);

        int len43 = len * 4 / 3;
        byte[] outBuff =
                new byte[(len43)                                          // Main 4:3
                        + ((len % 3) > 0 ? 4 : 0)                        // padding
                        + (breakLines ? (len43 / MAX_LINE_LENGTH) : 0)]; // New lines
        int d = 0;
        int e = 0;
        int len2 = len - 2;
        int lineLength = 0;
        for (; d < len2; d += 3, e += 4) {
            encode3to4(source, d + off, 3, outBuff, e, options);

            lineLength += 4;
            if (breakLines && lineLength == MAX_LINE_LENGTH) {
                outBuff[e + 4] = NEW_LINE;
                e++;
                lineLength = 0;
            } // end if: end of line
        } // end for: each piece of array

        if (d < len) {
            encode3to4(source, d + off, len - d, outBuff, e, options);
            e += 4;
        } // end if: some padding needed

        // Return value according to relevant encoding.
        try {
            return new String(outBuff, 0, e, PREFERRED_ENCODING);

        } catch (UnsupportedEncodingException uue) {
            return new String(outBuff, 0, e);
        }
    } // end encodeBytes

    /* ******** D E C O D I N G   M E T H O D S ******** */

    /**
     * Decodes four bytes from array <var>source</var> and writes the resulting
     * bytes (up to three of them) to <var>destination</var>. The source and
     * destination arrays can be manipulated anywhere along their length by
     * specifying <var>srcOffset</var> and <var>destOffset</var>. This method
     * does not check to make sure your arrays are large enough to accomodate
     * <var>srcOffset</var> + 4 for the <var>source</var> array or
     * <var>destOffset</var> + 3 for the <var>destination</var> array. This
     * method returns the actual number of bytes that were converted from the
     * Base64 encoding.
     * <p>
     * This is the lowest level of the decoding methods with all possible
     * parameters.
     * </p>
     *
     * @param source      the array to convert
     * @param srcOffset   the index where conversion begins
     * @param destination the array to hold the conversion
     * @param destOffset  the index where output will be put
     * @param options     options for getDecoabet
     * @return the number of decoded bytes converted
     * @see Base64#URL_SAFE
     * @see Base64#ORDERED
     * @since 1.3
     */
    @SuppressWarnings({"ConstantConditions"})
    protected static int decode4to3(byte[] source, int srcOffset,
                                    byte[] destination, int destOffset, int options) {
        byte[] DECODABET = getDecodabet(options);

        if (source[srcOffset + 2] == EQUALS_SIGN) {                 // Example: Dk==
            // Two ways to do the same thing. Don't know which way I like best.
            // int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 )
            // | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 );
            int outBuff =
                    ((DECODABET[source[srcOffset]] & 0xFF) << 18)
                            | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12);

            destination[destOffset] = (byte) (outBuff >>> 16);
            return 1;

        } else if (source[srcOffset + 3] == EQUALS_SIGN) {          // Example: DkL=
            // Two ways to do the same thing. Don't know which way I like best.
            // int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 )
            // | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
            // | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 );
            int outBuff =
                    ((DECODABET[source[srcOffset]] & 0xFF) << 18)
                            | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
                            | ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6);

            destination[destOffset] = (byte) (outBuff >>> 16);
            destination[destOffset + 1] = (byte) (outBuff >>> 8);
            return 2;

        } else {                                                    // Example: DkLE
            try {
                // Two ways to do the same thing. Don't know which way I like best.
                // int outBuff = ( ( DECODABET[ source[ srcOffset ] ] << 24 ) >>> 6 )
                // | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
                // | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 )
                // | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 );
                int outBuff =
                        ((DECODABET[source[srcOffset]] & 0xFF) << 18)
                                | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
                                | ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6)
                                | ((DECODABET[source[srcOffset + 3]] & 0xFF));

                destination[destOffset] = (byte) (outBuff >> 16);
                destination[destOffset + 1] = (byte) (outBuff >> 8);
                destination[destOffset + 2] = (byte) (outBuff);

                return 3;

            } catch (Exception e) {
                LOG.error("error decoding bytes at " + source[srcOffset] + ": " +
                        (DECODABET[source[srcOffset]]) + ", " + source[srcOffset + 1] +
                        ": " + (DECODABET[source[srcOffset + 1]]) + ", " +
                        source[srcOffset + 2] + ": " + (DECODABET[source[srcOffset + 2]]) +
                        ", " + source[srcOffset + 3] + ": " +
                        (DECODABET[source[srcOffset + 3]]), e);
                return -1;
            } // end catch
        }
    } // end decodeToBytes

    /**
     * Very low-level access to decoding ASCII characters in the form of a byte
     * array. Does not support automatically gunzipping or any other "fancy"
     * features.
     *
     * @param source  The Base64 encoded data
     * @param off     The offset of where to begin decoding
     * @param len     The length of characters to decode
     * @param options options for getDecodabet
     * @return decoded data
     * @see Base64#URL_SAFE
     * @see Base64#ORDERED
     * @since 1.3
     */
    public static byte[] decode(byte[] source, int off, int len, int options) {
        byte[] DECODABET = getDecodabet(options);

        int len34 = len * 3 / 4;
        byte[] outBuff = new byte[len34];           // Upper limit on size of output
        int outBuffPosn = 0;

        byte[] b4 = new byte[4];
        int b4Posn = 0;
        int i;
        byte sbiCrop;
        byte sbiDecode;
        for (i = off; i < off + len; i++) {
            sbiCrop = (byte) (source[i] & 0x7f);      // Only the low seven bits
            sbiDecode = DECODABET[sbiCrop];

            if (sbiDecode >= WHITE_SPACE_ENC) {       // Whitespace, Equals or better
                if (sbiDecode >= EQUALS_SIGN_ENC) {     // Equals or better
                    b4[b4Posn++] = sbiCrop;
                    if (b4Posn > 3) {
                        outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn, options);
                        b4Posn = 0;

                        // If that was the equals sign, break out of 'for' loop
                        if (sbiCrop == EQUALS_SIGN)
                            break;
                    } // end if: quartet built
                } // end if: equals sign or better
            } else {
                LOG.error("Bad Base64 input character at " + i + ": " + source[i] +
                        "(decimal)");
                return null;
            } // end else:
        } // each input character

        byte[] out = new byte[outBuffPosn];
        System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
        return out;
    } // end decode

    /**
     * Decodes data from Base64 notation, automatically detecting gzip-compressed
     * data and decompressing it.
     *
     * @param s the string to decode
     * @return the decoded data
     * @since 1.4
     */
    public static byte[] decode(String s) {
        return decode(s, NO_OPTIONS);
    }

    /**
     * Decodes data from Base64 notation, automatically detecting gzip-compressed
     * data and decompressing it.
     *
     * @param s       the string to decode
     * @param options options for decode
     * @return the decoded data
     * @see Base64#URL_SAFE
     * @see Base64#ORDERED
     * @since 1.4
     */
    public static byte[] decode(String s, int options) {
        byte[] bytes;
        try {
            bytes = s.getBytes(PREFERRED_ENCODING);

        } catch (UnsupportedEncodingException uee) {
            bytes = s.getBytes();
        } // end catch

        // Decode

        bytes = decode(bytes, 0, bytes.length, options);

        // Check to see if it's gzip-compressed
        // GZIP Magic Two-Byte Number: 0x8b1f (35615)

        if (bytes != null && bytes.length >= 4) {
            int head = (bytes[0] & 0xff) | ((bytes[1] << 8) & 0xff00);
            if (GZIPInputStream.GZIP_MAGIC == head) {
                GZIPInputStream gzis = null;
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                try {
                    gzis = new GZIPInputStream(new ByteArrayInputStream(bytes));

                    byte[] buffer = new byte[2048];
                    for (int length; (length = gzis.read(buffer)) >= 0; ) {
                        baos.write(buffer, 0, length);
                    } // end while: reading input

                    // No error? Get new bytes.
                    bytes = baos.toByteArray();

                } catch (IOException e) {
                    // Just return originally-decoded bytes

                } finally {
                    try {
                        baos.close();
                    } catch (Exception e) {
                        LOG.error("error closing ByteArrayOutputStream", e);
                    }
                    if (gzis != null) {
                        try {
                            gzis.close();
                        } catch (Exception e) {
                            LOG.error("error closing GZIPInputStream", e);
                        }
                    }
                } // end finally
            } // end if: gzipped
        } // end if: bytes.length >= 2

        return bytes;
    } // end decode

    /**
     * Attempts to decode Base64 data and deserialize a Java Object within.
     * Returns <tt>null</tt> if there was an error.
     *
     * @param encodedObject The Base64 data to decode
     * @return The decoded and deserialized object
     * @since 1.5
     */
    public static Object decodeToObject(String encodedObject) {
        // Decode and gunzip if necessary
        byte[] objBytes = decode(encodedObject);

        Object obj = null;
        ObjectInputStream ois = null;
        try {
            ois = new ObjectInputStream(new ByteArrayInputStream(objBytes));
            obj = ois.readObject();

        } catch (IOException e) {
            LOG.error("error decoding object", e);

        } catch (ClassNotFoundException e) {
            LOG.error("error decoding object", e);

        } finally {
            if (ois != null) {
                try {
                    ois.close();
                } catch (Exception e) {
                    LOG.error("error closing ObjectInputStream", e);
                }
            }
        } // end finally

        return obj;
    } // end decodeObject

    /**
     * Convenience method for encoding data to a file.
     *
     * @param dataToEncode byte array of data to encode in base64 form
     * @param filename     Filename for saving encoded data
     * @return <tt>true</tt> if successful, <tt>false</tt> otherwise
     * @since 2.1
     */
    public static boolean encodeToFile(byte[] dataToEncode, String filename) {
        boolean success = false;
        Base64OutputStream bos = null;
        try {
            bos = new Base64OutputStream(new FileOutputStream(filename), ENCODE);
            bos.write(dataToEncode);
            success = true;

        } catch (IOException e) {
            LOG.error("error encoding file: " + filename, e);
            success = false;

        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (Exception e) {
                    LOG.error("error closing Base64OutputStream", e);
                }
            }
        } // end finally

        return success;
    } // end encodeToFile

    /**
     * Convenience method for decoding data to a file.
     *
     * @param dataToDecode Base64-encoded data as a string
     * @param filename     Filename for saving decoded data
     * @return <tt>true</tt> if successful, <tt>false</tt> otherwise
     * @since 2.1
     */
    public static boolean decodeToFile(String dataToDecode, String filename) {
        boolean success = false;
        Base64OutputStream bos = null;
        try {
            bos = new Base64OutputStream(new FileOutputStream(filename), DECODE);
            bos.write(dataToDecode.getBytes(PREFERRED_ENCODING));
            success = true;

        } catch (IOException e) {
            LOG.error("error decoding to file: " + filename, e);
            success = false;

        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (Exception e) {
                    LOG.error("error closing Base64OutputStream", e);
                }
            }
        } // end finally

        return success;
    } // end decodeToFile

    /**
     * Convenience method for reading a base64-encoded file and decoding it.
     *
     * @param filename Filename for reading encoded data
     * @return decoded byte array or null if unsuccessful
     * @since 2.1
     */
    public static byte[] decodeFromFile(String filename) {
        byte[] decodedData = null;
        Base64InputStream bis = null;
        try {
            File file = new File(filename);
            byte[] buffer;

            // Check the size of file
            if (file.length() > Integer.MAX_VALUE) {
                LOG.fatal("File is too big for this convenience method (" +
                        file.length() + " bytes).");
                return null;
            } // end if: file too big for int index

            buffer = new byte[(int) file.length()];

            // Open a stream

            bis = new Base64InputStream(new BufferedInputStream(
                    new FileInputStream(file)), DECODE);

            // Read until done

            int length = 0;
            for (int numBytes; (numBytes = bis.read(buffer, length, 4096)) >= 0; ) {
                length += numBytes;
            }

            // Save in a variable to return

            decodedData = new byte[length];
            System.arraycopy(buffer, 0, decodedData, 0, length);

        } catch (IOException e) {
            LOG.error("Error decoding from file " + filename, e);

        } finally {
            if (bis != null) {
                try {
                    bis.close();
                } catch (Exception e) {
                    LOG.error("error closing Base64InputStream", e);
                }
            }
        } // end finally

        return decodedData;
    } // end decodeFromFile

    /**
     * Convenience method for reading a binary file and base64-encoding it.
     *
     * @param filename Filename for reading binary data
     * @return base64-encoded string or null if unsuccessful
     * @since 2.1
     */
    public static String encodeFromFile(String filename) {
        String encodedData = null;
        Base64InputStream bis = null;
        try {
            File file = new File(filename);

            // Need max() for math on small files (v2.2.1)

            byte[] buffer = new byte[Math.max((int) (file.length() * 1.4), 40)];

            // Open a stream

            bis = new Base64InputStream(new BufferedInputStream(
                    new FileInputStream(file)), ENCODE);

            // Read until done
            int length = 0;
            for (int numBytes; (numBytes = bis.read(buffer, length, 4096)) >= 0; ) {
                length += numBytes;
            }

            // Save in a variable to return

            encodedData = new String(buffer, 0, length, PREFERRED_ENCODING);

        } catch (IOException e) {
            LOG.error("Error encoding from file " + filename, e);

        } finally {
            if (bis != null) {
                try {
                    bis.close();
                } catch (Exception e) {
                    LOG.error("error closing Base64InputStream", e);
                }
            }
        } // end finally

        return encodedData;
    } // end encodeFromFile

    /**
     * Reads <tt>infile</tt> and encodes it to <tt>outfile</tt>.
     *
     * @param infile  Input file
     * @param outfile Output file
     * @since 2.2
     */
    public static void encodeFileToFile(String infile, String outfile) {
        String encoded = encodeFromFile(infile);
        OutputStream out = null;
        try {
            out = new BufferedOutputStream(new FileOutputStream(outfile));
            out.write(encoded.getBytes("US-ASCII")); // Strict, 7-bit output.

        } catch (IOException e) {
            LOG.error("error encoding from file " + infile + " to " + outfile, e);

        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (Exception e) {
                    LOG.error("error closing " + outfile, e);
                }
            }
        } // end finally
    } // end encodeFileToFile

    /**
     * Reads <tt>infile</tt> and decodes it to <tt>outfile</tt>.
     *
     * @param infile  Input file
     * @param outfile Output file
     * @since 2.2
     */
    public static void decodeFileToFile(String infile, String outfile) {
        byte[] decoded = decodeFromFile(infile);
        OutputStream out = null;
        try {
            out = new BufferedOutputStream(new FileOutputStream(outfile));
            out.write(decoded);

        } catch (IOException e) {
            LOG.error("error decoding from file " + infile + " to " + outfile, e);

        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (Exception e) {
                    LOG.error("error closing " + outfile, e);
                }
            }
        } // end finally
    } // end decodeFileToFile

    /* ******** I N N E R   C L A S S   I N P U T S T R E A M ******** */

    /**
     * A {@link Base64.Base64InputStream} will read data from another
     * <tt>InputStream</tt>, given in the constructor, and
     * encode/decode to/from Base64 notation on the fly.
     *
     * @see Base64
     * @since 1.3
     */


    public static class Base64InputStream extends FilterInputStream {
        private boolean encode;                     // Encoding or decoding
        private int position;                       // Current position in the buffer
        private byte[] buffer;                      // Buffer holding converted data
        private int bufferLength;                   // Length of buffer (3 or 4)
        private int numSigBytes;                    // Meaningful bytes in the buffer
        private int lineLength;
        private boolean breakLines;                 // Break lines at < 80 characters
        private int options;                        // Record options
        private byte[] decodabet;                   // Local copy avoids method calls

        /**
         * Constructs a {@link Base64InputStream} in DECODE mode.
         *
         * @param in the <tt>InputStream</tt> from which to read data.
         * @since 1.3
         */
        public Base64InputStream(InputStream in) {
            this(in, DECODE);
        } // end constructor

        /**
         * Constructs a {@link Base64.Base64InputStream} in either ENCODE or DECODE mode.
         * <p>
         * Valid options:
         *
         * <pre>
         *   ENCODE or DECODE: Encode or Decode as data is read.
         *   DONT_BREAK_LINES: don't break lines at 76 characters
         *     (only meaningful when encoding)
         *     &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
         * </pre>
         *
         * <p>
         * Example: <code>new Base64.Base64InputStream( in, Base64.DECODE )</code>
         *
         * @param in      the <tt>InputStream</tt> from which to read data.
         * @param options Specified options
         * @see Base64#ENCODE
         * @see Base64#DECODE
         * @see Base64#DONT_BREAK_LINES
         * @since 2.0
         */
        public Base64InputStream(InputStream in, int options) {
            super(in);
            this.breakLines = (options & DONT_BREAK_LINES) != DONT_BREAK_LINES;
            this.encode = (options & ENCODE) == ENCODE;
            this.bufferLength = encode ? 4 : 3;
            this.buffer = new byte[bufferLength];
            this.position = -1;
            this.lineLength = 0;
            this.options = options; // Record for later, mostly to determine which
            // alphabet to use
            this.decodabet = getDecodabet(options);
        } // end constructor

        /**
         * Reads enough of the input stream to convert to/from Base64 and returns
         * the next byte.
         *
         * @return next byte
         * @since 1.3
         */
        @Override
        public int read() throws IOException {
            // Do we need to get data?
            if (position < 0) {
                if (encode) {
                    byte[] b3 = new byte[3];
                    int numBinaryBytes = 0;
                    for (int i = 0; i < 3; i++) {
                        try {
                            int b = in.read();

                            // If end of stream, b is -1.
                            if (b >= 0) {
                                b3[i] = (byte) b;
                                numBinaryBytes++;
                            } // end if: not end of stream

                        } catch (IOException e) {
                            // Only a problem if we got no data at all.
                            if (i == 0)
                                throw e;

                        } // end catch
                    } // end for: each needed input byte

                    if (numBinaryBytes > 0) {
                        encode3to4(b3, 0, numBinaryBytes, buffer, 0, options);
                        position = 0;
                        numSigBytes = 4;

                    } else {
                        return -1;
                    } // end else

                } else {
                    byte[] b4 = new byte[4];
                    int i;
                    for (i = 0; i < 4; i++) {
                        // Read four "meaningful" bytes:
                        int b;
                        do {
                            b = in.read();
                        } while (b >= 0 && decodabet[b & 0x7f] <= WHITE_SPACE_ENC);

                        if (b < 0) {
                            break; // Reads a -1 if end of stream
                        }

                        b4[i] = (byte) b;
                    } // end for: each needed input byte

                    if (i == 4) {
                        numSigBytes = decode4to3(b4, 0, buffer, 0, options);
                        position = 0;

                    } else if (i == 0) {
                        return -1;

                    } else {
                        // Must have broken out from above.
                        throw new IOException("Improperly padded Base64 input.");
                    } // end
                } // end else: decode
            } // end else: get data

            // Got data?
            if (position >= 0) {
                // End of relevant data?
                if ( /* !encode && */position >= numSigBytes) {
                    return -1;
                }

                if (encode && breakLines && lineLength >= MAX_LINE_LENGTH) {
                    lineLength = 0;
                    return '\n';

                }
                lineLength++;                   // This isn't important when decoding
                // but throwing an extra "if" seems
                // just as wasteful.

                int b = buffer[position++];

                if (position >= bufferLength)
                    position = -1;

                return b & 0xFF;                // This is how you "cast" a byte that's
                // intended to be unsigned.

            }

            // When JDK1.4 is more accepted, use an assertion here.
            throw new IOException("Error in Base64 code reading stream.");

        } // end read

        /**
         * Calls {@link #read()} repeatedly until the end of stream is reached or
         * <var>len</var> bytes are read. Returns number of bytes read into array
         * or -1 if end of stream is encountered.
         *
         * @param dest array to hold values
         * @param off  offset for array
         * @param len  max number of bytes to read into array
         * @return bytes read into array or -1 if end of stream is encountered.
         * @since 1.3
         */
        @Override
        public int read(byte[] dest, int off, int len) throws IOException {
            int i;
            int b;
            for (i = 0; i < len; i++) {
                b = read();
                if (b >= 0) {
                    dest[off + i] = (byte) b;
                } else if (i == 0) {
                    return -1;
                } else {
                    break; // Out of 'for' loop
                }
            } // end for: each byte read
            return i;
        } // end read

    } // end inner class InputStream

    /* ******** I N N E R   C L A S S   O U T P U T S T R E A M ******** */

    /**
     * A {@link Base64.Base64OutputStream} will write data to another
     * <tt>OutputStream</tt>, given in the constructor, and
     * encode/decode to/from Base64 notation on the fly.
     *
     * @see Base64
     * @since 1.3
     */
    public static class Base64OutputStream extends FilterOutputStream {
        private boolean encode;
        private int position;
        private byte[] buffer;
        private int bufferLength;
        private int lineLength;
        private boolean breakLines;
        private byte[] b4;                          // Scratch used in a few places
        private boolean suspendEncoding;
        private int options;                        // Record for later
        private byte[] decodabet;                   // Local copy avoids method calls

        /**
         * Constructs a {@link Base64OutputStream} in ENCODE mode.
         *
         * @param out the <tt>OutputStream</tt> to which data will be written.
         * @since 1.3
         */
        public Base64OutputStream(OutputStream out) {
            this(out, ENCODE);
        } // end constructor

        /**
         * Constructs a {@link Base64OutputStream} in either ENCODE or DECODE mode.
         * <p>
         * Valid options:
         *
         * <ul>
         * <li>ENCODE or DECODE: Encode or Decode as data is read.</li>
         * <li>DONT_BREAK_LINES: don't break lines at 76 characters (only
         * meaningful when encoding) <i>Note: Technically, this makes your
         * encoding non-compliant.</i></li>
         * </ul>
         *
         * <p>
         * Example: <code>new Base64.Base64OutputStream( out, Base64.ENCODE )</code>
         *
         * @param out     the <tt>OutputStream</tt> to which data will be written.
         * @param options Specified options.
         * @see Base64#ENCODE
         * @see Base64#DECODE
         * @see Base64#DONT_BREAK_LINES
         * @since 1.3
         */


        public Base64OutputStream(OutputStream out, int options) {
            super(out);
            this.breakLines = (options & DONT_BREAK_LINES) != DONT_BREAK_LINES;
            this.encode = (options & ENCODE) == ENCODE;
            this.bufferLength = encode ? 3 : 4;
            this.buffer = new byte[bufferLength];
            this.position = 0;
            this.lineLength = 0;
            this.suspendEncoding = false;
            this.b4 = new byte[4];
            this.options = options;
            this.decodabet = getDecodabet(options);
        } // end constructor

        /**
         * Writes the byte to the output stream after converting to/from Base64
         * notation. When encoding, bytes are buffered three at a time before the
         * output stream actually gets a write() call. When decoding, bytes are
         * buffered four at a time.
         *
         * @param theByte the byte to write
         * @since 1.3
         */
        @Override
        public void write(int theByte) throws IOException {
            // Encoding suspended?
            if (suspendEncoding) {
                super.out.write(theByte);
                return;
            } // end if: supsended

            // Encode?
            if (encode) {
                buffer[position++] = (byte) theByte;
                if (position >= bufferLength) {                 // Enough to encode.
                    out.write(encode3to4(b4, buffer, bufferLength, options));
                    lineLength += 4;
                    if (breakLines && lineLength >= MAX_LINE_LENGTH) {
                        out.write(NEW_LINE);
                        lineLength = 0;
                    } // end if: end of line

                    position = 0;
                } // end if: enough to output

            } else {
                // Meaningful Base64 character?
                if (decodabet[theByte & 0x7f] > WHITE_SPACE_ENC) {
                    buffer[position++] = (byte) theByte;
                    if (position >= bufferLength) {               // Enough to output.
                        int len = decode4to3(buffer, 0, b4, 0, options);
                        out.write(b4, 0, len);
                        position = 0;
                    } // end if: enough to output

                } else if (decodabet[theByte & 0x7f] != WHITE_SPACE_ENC) {
                    throw new IOException("Invalid character in Base64 data.");
                } // end else: not white space either
            } // end else: decoding
        } // end write

        /**
         * Calls {@link #write(int)} repeatedly until <var>len</var> bytes are
         * written.
         *
         * @param theBytes array from which to read bytes
         * @param off      offset for array
         * @param len      max number of bytes to read into array
         * @since 1.3
         */
        @Override
        public void write(byte[] theBytes, int off, int len) throws IOException {
            // Encoding suspended?
            if (suspendEncoding) {
                super.out.write(theBytes, off, len);
                return;
            } // end if: supsended

            for (int i = 0; i < len; i++) {
                write(theBytes[off + i]);
            } // end for: each byte written

        } // end write

        /**
         * Method added by PHIL. [Thanks, PHIL. -Rob] This pads the buffer without
         * closing the stream.
         *
         * @throws IOException e
         */
        public void flushBase64() throws IOException {
            if (position > 0) {
                if (encode) {
                    out.write(encode3to4(b4, buffer, position, options));
                    position = 0;

                } else {
                    throw new IOException("Base64 input not properly padded.");
                } // end else: decoding
            } // end if: buffer partially full

        } // end flush

        /**
         * Flushes and closes (I think, in the superclass) the stream.
         *
         * @since 1.3
         */
        @Override
        public void close() throws IOException {
            // 1. Ensure that pending characters are written
            flushBase64();

            // 2. Actually close the stream
            // Base class both flushes and closes.
            super.close();

            buffer = null;
            out = null;
        } // end close

        /**
         * Suspends encoding of the stream. May be helpful if you need to embed a
         * piece of base640-encoded data in a stream.
         *
         * @throws IOException e
         * @since 1.5.1
         */
        public void suspendEncoding() throws IOException {
            flushBase64();
            this.suspendEncoding = true;
        } // end suspendEncoding

        /**
         * Resumes encoding of the stream. May be helpful if you need to embed a
         * piece of base640-encoded data in a stream.
         *
         * @since 1.5.1
         */
        public void resumeEncoding() {
            this.suspendEncoding = false;
        } // end resumeEncoding

    } // end inner class OutputStream

} // end class Base64